The blog highlights significant events and achievements in American aerospace history. The emphasis is on aviation and spaceflight. The blog seeks to inspire and motivate all Americans by honoring our country’s rich aerospace heritage.

Project Mercury’s Successful Failure

Fifty-two years ago this month, NASA launched Mercury-Atlas 3 (MA-3). While technically a flight test failure, the mission had the unexpected consequence of successfully demonstrating the Mercury spacecraft abort system under realistic emergency flight conditions.

Project Mercury was America’s first manned spaceflight program. Led by the National Aeronautics and Space Administration (NASA), the basic goals of Project Mercury were simple: (1) Orbit a manned spacecraft around the Earth, (2) investigate man’s ability to function in space and (3) recover both man and spacecraft safely.

The guidelines for achieving the above were equally straightforward: (1) Use existing technology and equipment wherever practical, (2) employ the most simple and reliable approach to system design, (3) place the spacecraft into orbit using an existing booster and (4) conduct a progressive and logical test program.

Project Mercury utilized a pair of existing military boosters converted for the manned flight role. The Redstone Intermediate Range Ballistic Missile (IRBM) was used for suborbital missions. Orbital missions were flown using the more powerful Atlas Intercontinental Ballistic Missile (ICBM). Both spacecraft-booster versions were tested a number of times prior to lofting men in to space.

The first suborbital flight test of the Mercury-Atlas combination, Mercury-Atlas 1 (MA-1), was conducted in July of 1960. Unfortunately, the booster structurally failed and exploded about a minute into flight. A second attempt at flying a Mercury-Atlas suborbital mission followed in February of 1961. Things worked out much better this time around as Mercury-Atlas 2 (MA-2) successfully met all test objectives.

The next step in the Mercury-Atlas test series was to attempt at a single orbit mission. This was the primary objective of Mercury-Atlas 3 (MA-3). The subject Mercury spacecraft carried an astronaut simulator intended to mimic the inhalation and exhalation of gas, heat and water vapor characteristics of a man.

On Tuesday, 25 April 1961, Mercury-Atlas 3 lifted-off from Cape Canaveral’s LC-14 at 16:15 UTC. As the vehicle thundered away from the launch pad, all systems functioned as planned. However, the Range Safety Officer (RSO) terminated the mission 43.3 seconds after lift-off as the Atlas launch vehicle began to stray from the intended flight trajectory. The launch vehicle’s autopilot had failed.

Interestingly, the Mercury spacecraft’s abort sensing system and rocket escape system worked exactly as designed. The Mercury spacecraft was safely rocketed away from the exploding booster and lofted to an altitude of 24,000 feet. The parachute recovery system deployed successfully and gently deposited the spacecraft about 4 nm downrange of the launch site. All of this in what was a true in-flight emergency. Had an astronaut been onboard, he would have survived the destruction of the booster.

As a footnote to this story, the Mercury spacecraft flown on MA-3 was found to be in such good condition that it was used for the very next Mercury-Atlas orbital attempt. Happily, that mission, Mercury-Atlas 4 (MA-4) successfully achieved earth orbit and met all flight objectives in September of 1961.